Tuesday, May 20, 2008

Emmett Holman has an interesting article in the latest Journal of Consciousness Studies that’s also very timely in light of the discussion in the prior post. Surveying several approaches to a Russellian theory of mind (RTM, to use his abbreviation), Holman observes that most have been panpsychist, but at least one is presented as a version of physicalism, and some are neutral monist interpretations. Holman takes a look at the landscape to see what the advantages of competing approaches might be. He doesn’t come to a strong conclusion, but thinks that it’s not clear that a panpsychist approach should be preferred.

Setting the stage, Holman outlines the basis for interest in RTM: “The advertising for RTM is that it constitutes just the insight needed to break (what many see as) the current impasse on the mind-body problem.” He explains in particular that RTM is a response to dissatisfaction with “mainstream” physicalism, defined as the stance that “the mental supervenes on the physical as the physical is characterized by physical theory” (emphasis original).

According to RTM, the problem is that physical theory characterizes the entities in its domain strictly extrinsically, in terms of causal, functional and other relations in which they stand to each other and to our experience. Nowhere does physical theory inform us as to the intrinsic nature of the entities; and it can only be in virtue of this intrinsic nature that the entities have the causal powers or dispositional properties they exhibit. The question arises: can we know what this intrinsic nature is?

Well, the Russellian notes that conscious experience acquaints us with intrinsic phenomenal properties. In taking this point further, there are several possible views to take of the intrinsic nature of basic entities.

1. First, a monistic panpsychism posits that this intrinsic nature is essentially mental or phenomenal, and thus the mental dimension of human experience derives from the inherent mental quality of all nature.

2. A Russellian version of physicalism might say that the mental emerges or otherwise is a consequence of a configuration of physical (defined here minimally as non-mental) intrinsic properties.

Looking critically initially at the second (physicalist) option, Holman notes the objection that it might be seen to offer an epistemic gap just as large as conventional mental/physical gap. Well, perhaps not, since a combination of non-mental intrinsic properties giving rise to mental intrinsic properties may be seen as superior to trying to get mental intrinsic properties from non-mental extrinsic ones.

Still, isn’t the panpsychist option superior? Here, however, Holman looks critically upon another “gap” faced by this option. Since the idea of an elementary particle having mental states like we have seems ridiculous, advocates of panpsychist theories typically speak of the basic intrinsic properties as “proto-phenomenal” or “proto-experiential” etc. Elementary entities are sometimes said to have a “low-level” version of experience or mentality, or have properties that are in some way just analogous to human mentality. As long as we lack an account of how the simpler properties give rise to the more robust ones, a troubling gap persists here.

How about a neutral monism? Holman sketches his own version of how a neutral monist approach to the nature of these intrinsic properties might go. “The relevant fundamental intrinsic property [would be] a determinable property which is itself neither experiential nor non-experiential”(emphasis original). Its determinates can manifest degrees of experientiality along a zero to one scale.

Before pursuing this line of thought further, Holman circles back to see if any panpsychist accounts introduced concepts more amenable to coming in degrees than simply the concepts of the phenomenal, the experiential, or the like. One concept he sees which may have promise is the notion of “subjective unity”, which he finds, among other places, in Gregg Rosenberg’s work. Conscious states differ from the rest of nature in that they have (quoting Rosenberg) a “complex but not composite” character. Conscious states can be very rich and diverse (including various sensory modalities) yet they have a special kind of unity which binds them together. They can’t be simply decomposed into parts the way physical systems can be. The components can only exist as part of the unified state.

If this idea has merit, then maybe subjective unity can be “scaled down” gradually or in degrees in way that appears more intelligible than was the case for the notions of mentality or experience as such. In fact this could perhaps support a neutral monism in the following sense: the most basic entity considered alone has no experiential value. But once multiple entities are considered, they can be participants in a subjective unity with an attendant degree of experientiality.

Holman doesn’t take this past a sketch, and he also considers some other variations very briefly. He concludes that more work needs to be done on Russellian theories and it is not clear to him which avenue is superior. But he maintains that it is not clear to him from his survey that panpsychist versions are inherently to be preferred. At the same time, he doesn’t’ think much of the “physicalist” option either. Holman’s sympathies appear to lie with neutral monism, but he awaits a more full-fledged theory to consider here.

Postscript 1: Like many others who have written about this subject, Holman’s main references to Russell himself are to 1927’s Analysis of Matter. I note that Carey Carlson’s book relies much more on 1948’s Human Knowledge, which I have not read. I wonder if Carlson’s much greater emphasis on the importance of viewing RTM though the lens of an event ontology vs. an object ontology can be linked at least in part to this fact. I’ll have to get the book.
{UPDATE 14 June 2008: Having read both books -- the event ontology is firmly in place in both. The basic framework did not change from 1927 to 1948. To pick up the neutral monism from Russell without picking up the event ontology on which it rests is simply to miss too much of the point.]

Postscript 2: Note that Holman’s lone example of the “physicalist” version of RTM is from an older paper from Daniel Stoljar. Stoljar’s position in his more recent book (Ignorance and Imagination) has evolved and he doesn’t specifically champion this version of RTM. His endorsement of physicalism in the book relies on the epistemic argument that we just don’t know enough to say that the non-mental couldn’t be the supervenience base for the mental. The unknown “experience-relevant non-experiential facts” could be intrinsic, extrinsic or both. I have a series of posts on this book under the label Stoljar.

Tuesday, May 13, 2008

“The mind-body problem demands a description of how the mental and physical parts of the world go together to make up the whole. The problem was solved around 1927 by Bertrand Russell and Alfred North Whitehead.”

Since I think the Russellian stance on the mind-body problem is superior to the traditional options of dualism and materialism and also think Whitehead’s speculative process metaphysics was far ahead of its time, I was excited to see this passage and curious as to how well Carlson would back it up over the course of a short book. After reading the book I can say I think he did an excellent job in showing how the ideas from these thinkers can be put together into a compelling argument for a more coherent view of the world: that of a causal network of events which share a character which naturally underpins what we characterize as the mental and physical.Carlson is an independent thinker and writer from Minneapolis who studied philosophy some years ago and concluded Russell and Whitehead had it right. He says he was perplexed that this seemed unappreciated. While he ended up pursuing a career outside philosophy, he finally was able to put together his views on the matter on paper (he put out this book in 2004). He and I corresponded via e-mail recently and that led to my interest in reading his work.

Both Russell and Whitehead explained why you cannot identify the world with our mathematical descriptions of it: you leave out the intrinsic qualitative character of the world we know via experience. Both philosophers showed, in somewhat different ways, that what we think of as mental events and physical events can both fit into a picture of a causal network, whereas our usual intuition of the world as a spatial container holding static objects or substance won’t work – whether one posits one kind of object or two.

Carlson’s outstanding contribution is to carefully describe what this ontology of causal relations can do: it can describe space-time and all that’s in it while also accommodating mental events. He then shows how scientific theory really is an elucidation of a causal web and how it must actually fit into our network of experiences in order to be formulated. This leads to the final postulate that all nature has a sentient character, and that this best explains how mind and world are unified. While I was already sold on this idea, I think Carlson’s book may convince other readers of the merits of a panexperientialist solution to the mind-body problem inspired by sound philosophy of science.

All in all, this book does credit to its ambitious title. Along the way, it is also a fine exposition of some of the work of two of our greatest twentieth century thinkers.

My chapter-by-chapter notes and comments follow below.

---------------------------------------------------------------------------------In the first chapter, he lays out the problem. Like others, he locates the “hard” problem for materialism in the raw feeling of being or sentience. He speaks of “the sensorium” of unified experience. If materialism or physicalism sees the mathematically characterized world as all that exists, then it does not include nor will it explain sentience – that which is given in phenomenal experience. The mind-body problem could be called the “phenomenology-physics problem”, he says (p.13).

Chapter 2 deepens this discussion, taking a closer look at the history of physics. Even with the advent of modern physics, taking quantum field theory for example, there seems to be a left-over tendency to conceive the world as physical matter or energy existing in a container of physical space. There certainly is no role for mental features in such a worldview.

After touching very briefly on some historical philosophical perspectives in Chapter 3, we start to move toward the solution in Chapter 4 with a review of Russell’s analysis of the world in terms of structure and relations (and specifically causal structure and relations). Here, Carlson pulls relevant passages from Russell’s Human Knowledge (this book I had not read – I had read the Analysis of Matter). Structure is defined as a pattern of relations. Relations relate terms of a class (which is just any definite set of entities). Russell discusses a variety of types of relations: dyadic and higher-order, symmetric/asymmetric, transitive/intransitive. Relata, relations and structure together form a complex, which is a whole or a fact. This approach can be seen as applying to pure mathematics, and it can also be seen as characterizing the phenomena of the world, as presented to us. In physics, we apply mathematics to real world phenomena. But one can’t identify the phenomena as identical with the mathematical description. Here’s a quote from Russell: “There is, however, a very definite limit to the process of turning physics into logic and mathematics; it is set by the fact that physics is an empirical science, depending for its credibility upon relations to our perceptive experiences.”

While Russell’s philosophy of science is obviously not unknown, commentators I have read don’t always stress the role of relations in his analysis. The fact that the world is made of relations (rather than the static objects or “stuff” of our intuitions) is a key point for Carlson, which will also provide the link to the work of Whitehead (Carlson notes with interest the history here: while Russell and Whitehead were famous for their collaboration on the Principia Mathematica, that seemed to be the end of their formal work together – yet the “fingerprints” of this shared history writing the Principia can be seen in their similar later critiques of the role of logic and mathematics in science).

In Chapter 5, Carlson argues that the most basic feature of physics, space-time, can be analyzed in terms of causal structure. Here he gives credit to the role the theory of special relativity played in showing the way forward: in it we can see how causal relations could be responsible for both spatial and temporal order. Since causal relations are relations in time, it is the temporal ordering of events which is fundamental, while the spatial is derived.

Since “real” causation is an asymmetric relation, Carlson shows how we can use arrows to graphically illustrate causal relations. One can see how “space-like” and “time-like” relations between events arise from a causal structure. He then shows how a “particle” could be defined as a recurring pattern of activity -- a certain geometric pattern repeated along a time-like route in a larger causal lattice). One of Carlson’s interesting ideas is that since different numbers of arrows could connect two given events, one gets a notion of relative temporal frequency. This allows for the introduction of the concept of energy into a causal network of events.

With these examples, we can see how the notion of the physical world (traditionally seen as a spatial container plus stuff inside it) can be replaced by a network of time-like causal relations alone. This is consistent with a basic notion of what science does: it looks at the world and analyzes what comes before what. Carlson notes that progress in physics eventually arrived at quantum events – discrete events which “do not admit of further before-and-after analysis” (p.71). These elementary events and the causal connections among them constitute the world. So the physical world is not space plus what it contains, but rather time-like causal relations only. And this picture is one which allows for the solution to the mind-body problem.

In Chapter 6, Carlson argues that mental events can be located in the causal network in the same way as “physical” events. Our experience can be seen as participation in a sequence of time-ordered mental events. So, do mental and physical events “interact”? Interactionist dualism is often seen as an incoherent perspective on the mind-body problem. But we’re not talking about static substances. Russell reminds us that mental events are unavoidably part of the causal network which describes the world, since the structure of physics has to empirically connect to the sensations of the physicist. Mental and physical events are interspersed in the causal network. Now, our human experiences seem very different than the entities of micro-physics, but when you break down it all down, both can be situated in a causal network. “The distinction between mental and physical now hinges upon the assumption that mental events are characterized by sensory qualities, while physical events are not. (p.87)”

Carlson does a good job in this chapter in trying to break down our intuitions, and it’s hard to do it justice in this summary. But I think he does a good job showing how an event ontology can situate the mental as well as the physical in one world-web. Some questions arise here: what are the base-level indivisible quantum events connected by the arrows of causal relations, such that they can form the basis for everything? What is the quantum event’s intrinsic nature?

Heading toward an answer to this is the discussion in Chapter 7. While in Chapter 6 Carlson tries to show how mental events can be situated in a world we think of as physical, in Chapter 7 he (again leveraging Russell) shows that we really do need to invert this. All physical theorizing and experimentation does take place within the context of mental events. This shows there really is no reason to distinguish between the two kinds of events. Science gives us nothing but causal structure. We know some causal events have a mental character and the physical events are only known via the mental.

Russell “stops” at this point. He was agnostic about whether the intrinsic character of the physical (non-directly experienced) events was also of mental or sentient character in any way. He said we just don’t know. Phenomenal character is the only kind of intrinsic quality we’re familiar with, but we can’t know the intrinsic character of the rest. Given this stance, some have cast Russell’s theory as a form of neutral monism.

But Carlson wants to go further, so he states that his final chapter (no.8) “belongs to Whitehead”. Whitehead’s critique of materialism was very similar to Russell’s (for example the first several chapters in his Science and the Modern World). But in Process and Reality, he was much more ambitious. Among other things in that work, he goes ahead and postulates that all events have a sentient character. Carlson endorses the idea that it is both fitting and simpler to posit this, rather than to assume there is some other unknown form of intrinsic content. Further, under this assumption, the world just makes more sense in terms of unifying the human experience with the rest of the world. In Whitehead’s theory, the causal structure of all events are grounded and ordered in the same way.

Carlson does a good job in just a few pages in summarizing some of Whitehead’s ideas. This is difficult because of all of Whitehead’s invented terminology and his hard-to-penetrate prose “style”. Whitehead’s treatment of causation is richer than what Carlson has discussed so far, including the transition from subjective to objective poles for each event, and the inclusion of purpose and self-determination as a causal factor in the setting the course of events. He also discusses Whitehead’s treatment of the unactualized possibilities (eternal objects) which are presupposed by the view that the temporal process establishes the contingent facts of the world. He finally then discusses Whitehead’s theory of how events (occasions) are organized into enduring societies and how the parts work to satisfy the determination of the whole -- a template for describing the human mind.

I don’t have very much critical to say about the book except as it relates to my thinking about what might be added to expand the discussion. Events and causation are the primitives in the theory. Until the final chapter on Whitehead, how causation works is not described. We can probably improve on Whitehead in this area (Gregg Rosenberg’s theory would be one to possibly consider). Related to this would be drawing more connections to an interpretation of quantum mechanics to better describe what is going on in an elementary quantum event and what the status is of wavefunction associated with a quantum system. Also, we need to someday improve on Whitehead with regard to the combination or composition problem – explaining how micro-events clump up into macro-events like the ones making up human experience.

Thursday, May 01, 2008

An article entitled “Cephalopod consciousness: Behavioral evidence” by Jennifer A. Mather has appeared in the latest issue of the journal Consciousness and Cognition. In it, she looks at a variety of studies to assess the evidence that cephalopods have a form of primary (as opposed to higher-order) consciousness. This is intended as a follow-up on the previous paper on animal consciousness by Seth, Baars and Edelman published in the journal in 2005 (looking at indications of consciousness from the perspective of Bernard Baars’ “global workspace theory”). I had briefly blogged about this article and others on animal consciousness in old posts here and here.

Cephalopods are particularly interesting. First, they’re just cool. More importantly, the convergent evolution of the mind in a lineage so distant from the human tells us something important, I think, about how the building blocks of consciousness are embedded deeply in the fabric of the natural world.

Setting aside higher-order reflective self-consciousness and language-possession, humans likely share with some animals a primary or core consciousness tied to their active engagement with the world. With vertebrates, the symmetries in neurological structure are one aid to assessing the potential for such a shared trait. With cephalopods this is more difficult, but certain brain anatomy-behavior linkages can be explored, and beyond that the full range of behaviors can be surveyed for clues. Mather conducts a meta-analysis of a long list of cephalopod studies to search for this evidence. She finds several areas which offer good support for the existence of primary consciousness in these animals.

With regard to brain anatomy-behavior linkages, she finds similarities in lateralization of functions (which may be linked to consciousness): this is demonstrated in the eye use of octopi in particular but another example is found in the skin displays of squid.

Sleep pattern is another clue to consciousness in animals, and there are similarities found between cephalopods and mammals here.

The developmental aspect of mind is explored: cuttlefish develop improved memory as their brains develop with some parallel to the development of young mammals and human infants.

Learning is another general area explored in many studies and Mather looks at these in some depth. Parallels to “higher” vertebrates are found. Another section explores the sense of self and self-monitoring. Also of interest is that octopi have demonstrated personality differences, and squid have shown intriguing signs of primitive language capability in their skin displays.

All this would suggest cephalopods are good candidates for animals which possess primary consciousness.

UPDATE: I see there was good blog commentary on an earlier online version of this work here and here.